test(vision): fix stub-mode tests; close the testing-gap wiki note

The two failing apps/vision smoke tests assumed stub mode but the local .env sets
VISION_RECOGNIZER=fast_alpr (real-model work, 2026-06-19), so the app built the real
recognizer: /health reported "fast_alpr" not "stub", and /analyze on garbage bytes
422'd (real decode reject) instead of returning the empty stub contract.

Fix is test isolation: a conftest autouse fixture pins VISION_RECOGNIZER=stub for the
session (an OS env var overrides the .env in pydantic-settings), restoring it after.
vision 7/7.

Updates wiki/concepts/booth-console.md (the "no automated tests" Open note now reflects
the coverage that landed) and appends wiki/log.md.

Full workspace: shared 87, server 75, devices 18, web 17, vision 7 = 204 tests across
8 turbo test tasks, 0 failures; build/lint 14/14.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/vision/tests/conftest.py

@@ -0,0 +1,28 @@
+"""Shared test fixtures.
+
+The stub-mode smoke tests must be deterministic regardless of the developer's local
+apps/vision/.env (which may set VISION_RECOGNIZER=fast_alpr for real-model work). An OS
+environment variable takes precedence over the .env file in pydantic-settings, so we
+force stub mode for the whole test session before the app's lifespan builds the
+recognizer. Tests that exercise the real recognizer set their own override explicitly.
+"""
+
+from __future__ import annotations
+
+import os
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def _force_stub_recognizer() -> None:
+    """Pin the recognizer to the model-free stub for every test (overrides .env)."""
+    prev = os.environ.get("VISION_RECOGNIZER")
+    os.environ["VISION_RECOGNIZER"] = "stub"
+    try:
+        yield
+    finally:
+        if prev is None:
+            os.environ.pop("VISION_RECOGNIZER", None)
+        else:
+            os.environ["VISION_RECOGNIZER"] = prev